Counting chamber provided with a reference and method for manufacturing a counting chamber provided with a reference

ABSTRACT

Disclosed is a counting chamber for optical detection of particles that are present in a fluid, comprising two substantially transparent and substantially parallel plates of material, between which the fluid can be introduced. At least one of the plates includes a visible reference, which comprises a relief formed on the surface of the plate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a counting chamber for optical detection ofparticles that are present in a fluid, comprising two substantiallytransparent and substantially parallel plates of material, between whichthe fluid can be introduced, wherein at least one of said platesincludes a visible reference.

2. Description of the Related Art

Such counting chambers can be used for examining blood, urine or spermand all other fluids.

The term reference is understood to means a visible image, in particularan image which visibly delimits parts of the counting chamber when aperson is viewing the counting chamber through a microscope. Theparticles that are present in the fluid can be quantified in that caseby counting or estimating the number of particles that are present in aspecific delimited section.

The reference can also be a gauge, which is divided into units oflength, so that it is possible to determine the size of the particlesthat are present in the fluid.

It is important that the reference, or the image, consists of lineswhich reduce the visibility of the fluid to a minimum degree. It ispossible to use extremely thin lines for that purpose, but such linesare difficult to place and, in addition, they do not show up very wellat all times.

The object of the invention is to provide a counting chamber including areference which reduces the degree of visibility in the counting chamberonly slightly, and which is nevertheless readily perceptible to the eye.

Another object of the invention is to provide a counting chamber whichmeets the necessary quality requirements, and which can nevertheless bemanufactured at low cost. For hygienic reasons, single use is stronglypreferred.

SUMMARY OF THE INVENTION

According to the invention, in order to accomplish that objective, thereference comprises a relief formed on the surface of one of saidplates. In practice it has become apparent that a line formed on asurface of at least one of the plates of material in the form of arelief, preferably in the form of a rib projecting from the surface,shows up very well, even if it has a small width, when counting chamberis being viewed through a microscope.

Preferably, the two plates of material are inseparably joined together,for example by means of a glued joint, thus providing a relativelyinexpensive, disposable product, that is, a counting chamber for singleuse.

Preferably, the relief is formed on the inner surface of one of theplates of material, as a result of which the relief extends into thefluid that is present in the counting chamber, as it were.

Such a relief is preferable to a relief that has been formed in a plateof material by, for example, being scratched or etched therein. A thin,straight line is difficult to realise by means of such a method.

In one preferred embodiment, said two plates of material and said reliefare transparent, wherein the material of the plates is preferably glass.

In another preferred embodiment, said material is a plastic.

Preferably, said relief consists of a material which extends outwardsfrom the surface of the plate of material, that is, from said plate ofmaterial into the space within the counting chamber.

In one preferred embodiment, said reference comprises a gridsubstantially consisting of lines that intersect each otherperpendicularly. In that case the space within the counting chamberappears to be divided into sections upon viewing the contents of thecounting chamber, and the number of particles in one section can becounted or estimated.

When the lines, although being readily visible, consist of a transparentmaterial, it is also possible to perceive the particles that are locatedon a line, which is advantageous when counting said particles.

In another preferred embodiment, said reference comprises a ruleprovided with a graduation, which makes it possible to determine thesize of the particles that are present in said fluid.

Preferably, said relief has been formed in a material different from thematerial of the plate, for example a synthetic material such as an epoxyresin or an acrylate, which has been applied to the material of theplate. Preferably, said other material has been applied to the plate ofmaterial in liquid form and subsequently been compressed by means of astamp, in which a negative of the relief is present. In that case it ispossible to form a relief in the shape of thin, straight ribs, whichconstitute the reference. After the relief has been formed in thismanner, said other material can be cured by exposing it to radiation,for example UV radiation. It is also possible to use infrared radiation.

In another preferred embodiment, said relief comprises grooves thatextend into said other material from the surface thereof.

The invention furthermore relates to a method for manufacturing acounting chamber for optical detection of particles that are present ina fluid, wherein two substantially transparent plates of material arejoined together in parallel relationship, so that a space is createdbetween said plates, into which said fluid can be introduced, wherein atleast one of said plates is previously provided with a visiblereference, wherein said reference is formed by forming a relief on thesurface of one of said plates.

Preferably, a different material in liquid form is applied to said plateof material, after which it is compressed by means of a stamp, in whicha negative of said relief is present. Preferably, said other material iscured by exposing it to UV radiation.

The invention furthermore relates to a method for optical detection ofparticles that are present in a fluid, wherein said fluid is introducedinto a counting chamber comprising two substantially transparent andsubstantially parallel plates of material, wherein at least one of saidplates is provided with a visible reference, wherein said referencecomprises a relief that has been formed on the surface of one of saidplates.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to explain the invention more fully, an embodiment of acounting chamber will now be explained in more detail with reference tothe drawing.

FIG. 1 is a top plan view of a counting chamber;

FIG. 2 is a side elevation of the counting chamber of FIG. 1;

FIG. 3 is a sectional view along line III—III in FIG. 1; and

FIG. 4 is a larger-scale detail of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The figures show the embodiment only schematically, and for the sake ofclarity the dimensions are not shown in their actual proportions in allcases.

FIGS. 1 and 2 show in elevation the counting chamber consisting of twoglass plates 1, 2, which are joined by film of glue 3. Said film of glue3 does not cover the entire area between the glass plates 1, 2, but onlythe area 4 in FIG. 1, which surrounds an area that forms chamber 5.

Film of glue 3 has a specific thickness, in order to space the glassplates 1, 2 a specific, constant distance apart. Said specific thicknessof the film of glue 3 can be achieved by putting spherical particlesinto the glue, for example glass spheres having a diameter equal to thedesired distance between glass plates 1, 2.

Chamber 5 is enclosed by the two glass plates 1, 2 and the film of glue3, therefore. It is possible to gain access to chamber 5 from theoutside via openings 6, 12. Chamber 5 can be filled through one of saidopenings 6, 12 with a fluid which contains particles that need to bequantified or classified. The other opening 12, 6 thereby functions tovent chamber 5.

FIG. 3 is a sectional view of the counting chamber, and FIG. 4 shows theencircled part 7 of FIG. 3 on a larger scale, so that the reference 8that is present on lower glass plate 1 is visible.

Reference 8 consists of a film of epoxy resin that has been applied tolower glass plate 1, in which a relief has been formed. In theillustrated embodiment, said relief consists of two groups of elevenmutually parallel ribs each, which extend perpendicularly to each other.

FIG. 4 shows one of said groups of ribs 9 in sectional view. A rib 10extending perpendicularly thereto is shown in elevation. Thecircumference of the film of epoxy resin is substantially circular, asis shown in FIG. 1.

Said two groups of eleven ribs 9, 10 each form a grid comprising ahundred square sections, as is shown in FIG. 1. Also other patternscomprising more or fewer ribs are possible, wherein the angle that ribsinclude between themselves may also be an angle other than a straightone.

The spacing between the two glass plates 1, 2 and the thickness ofreference 8 must be selected so that reference 8 and the upper glassplate 2 are spaced a desired distance apart. After all, said spacingdetermines the amount of fluid that is present within a grid sectionwhen chamber 5 is being viewed through a microscope. The number ofparticles that are present in said amount can be counted or estimatedthereby.

In FIG. 1, reference 8 is shown unproportionally large. The spacingbetween the ribs of the grid is, for example, 0.001–1 mm. The spacingbetween the glass plates 1, 2 is, for example, 0.1 mm.

Reference 8 may also comprise a rule or other gauge provided with agraduation, whether or not in combination with the grid.

Reference 8 has been formed on glass plate 1 by compressing a drop of aliquid epoxy resin on glass plate 1 by means of a stamp, in which anegative of the relief is present. The curing process of the epoxy resincan be accelerated by exposing it to UV radiation, which can take placethrough glass plate 1.

In order to make it easier to detach of the stamp, a suitable substancecan be applied to the surface thereof, which is done each time beforethe stamp comes into contact with the epoxy resin or other material.

The illustrated embodiment is merely an example of a counting chamber,also other embodiments are possible.

1. A counting chamber for optical detection of particles that arepresent in a fluid, comprising two substantially transparent andsubstantially parallel plates of a first material, between which thefluid can be introduced, wherein at least one of said plates includes avisible reference comprising a relief formed on a surface of said atleast one of said plates in a second material different from said firstmaterial of said at least one of said plates, which second material hasbeen applied to said at least one of said plates, wherein said secondmaterial is a curable synthetic material.
 2. The counting chamberaccording to claim 1, wherein said two plates are inseparably joinedtogether.
 3. The counting chamber according to claim 2, wherein said twoplates are inseparably joined together by a glued joint.
 4. The countingchamber according to claim 1, wherein said relief is formed on an innersurface of said at least one of said plates.
 5. The counting chamberaccording to claim 1, wherein said first material is glass.
 6. Thecounting chamber according to claim 1, wherein said first material is aplastic.
 7. The counting chamber according to claim 1, wherein saidrelief consists of a material which extends outwards from said surfaceof said at least one of said plates.
 8. The counting chamber accordingto claim 1, wherein said reference comprises a grid substantiallyconsisting of lines that intersect each other perpendicularly.
 9. Thecounting chamber according to claim 1, wherein said reference comprisesa graduation.
 10. The counting chamber according to claim 9, whereinsaid graduation is a rule.
 11. The counting chamber according to claim1, wherein said second material is an epoxy resin or an acrylate. 12.The counting chamber according to claim 1, wherein said second materialhas been applied to said at least one of said plates in liquid form andsubsequently been compressed by means of a stamp, in which a negative ofsaid relief is present.
 13. The counting chamber according to claim 12,wherein said second material is cured by exposing said second materialto radiation.
 14. The counting chamber according to claim 13, whereinsaid radiation is UV radiation.
 15. The counting chamber according toclaim 1, wherein said relief comprises grooves that extend into saidsecond material from a surface thereof.
 16. A method for opticaldetection of particles that are present in a fluid, comprising the stepof introducing said fluid into a counting chamber comprising twosubstantially transparent and substantially parallel plates of material,wherein at least one of said plates is provided with a visible referencecomprising a relief that has been formed on a surface of said at leastone of said plates in a material different from the material of said atleast one of said plates, which has been applied to said at least one ofsaid plates, wherein said different material is a curable syntheticmaterial.